Wastegates and wastegate components

ABSTRACT

A wastegate assembly can include a plug configured to plug a wastegate opening where the plug includes a concave, at least partially spherical surface; a shaft configured for receipt by a bore in a wastegate chamber; and a rotatable arm extending from the shaft where the arm includes a convex, at least partially spherical surface configured for contacting the concave, at least partially spherical surface of the plug for a closed orientation of the plug with respect to the wastegate opening.

RELATED APPLICATIONS

This application is a divisional of an application having U.S. Ser. No.13/047,177, filed 14 Mar. 2011, issued as U.S. Pat. No. 8,820,709, 2Sep. 2014, which is incorporated by reference herein.

TECHNICAL FIELD

Subject matter disclosed herein relates generally to turbomachinery forinternal combustion engines and, in particular, to wastegates andwastegate components.

BACKGROUND

An exhaust wastegate is typically a valve that can be controlled toselectively allow at least some exhaust to bypass an exhaust turbine.Where an exhaust turbine drives a compressor for boosting inlet pressureto an internal combustion engine, a wastegate provides a means tocontrol the boost pressure.

A so-called internal wastegate is integrated at least partially into aturbine housing. An internal wastegate typically includes a “flapper”valve, a crank arm, a shaft or rod, and an actuator. In a closedposition, a wastegate flapper or plug needs to be seated with sufficientforce to effectively seal an exhaust bypass (e.g., to prevent leaking ofexhaust from a high pressure exhaust supply to a lower pressure region).Often, an internal wastegate is configured to transmit force from an armto a plug. During engine operation, load requirements for a wastegatevary with pressure differential. High load requirements can generatehigh mechanical stresses in a wastegate's kinematics components, a factwhich has led to significantly oversized component design to meetreliability levels (e.g., as demanded by engine manufacturers).Reliability of wastegate components for gasoline engine applications isparticularly important where operational temperatures and exhaustpulsation levels can be quite high.

Various examples of wastegates and wastegate components are describedherein, which can optionally provide for improved kinematics, reducedexhaust leakage, etc., when compared to conventional wastegates andconventional wastegate components.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the various methods, devices,assemblies, systems, arrangements, etc., described herein, andequivalents thereof, may be had by reference to the following detaileddescription when taken in conjunction with examples shown in theaccompanying drawings where:

FIG. 1 is a diagram of a turbocharger and an internal combustion enginealong with a controller;

FIG. 2 is a perspective view of an assembly with a wastegate;

FIG. 3 is a perspective view of an assembly with a wastegate;

FIG. 4 is a perspective view and a cross-sectional view of an assemblywith a wastegate;

FIG. 5 is a top view of a shaft and arm component, a side view of anarm, and a cross-sectional view of an assembly with a conventionalwastegate arm;

FIG. 6 is a cross-sectional view of the assembly of FIG. 5 demonstratingkinematics of exhaust leakage;

FIG. 7 is a top view of an example of a shaft and arm component, a sideview of an example of an arm and a cross-sectional view of an example ofan assembly with a wastegate arm demonstrating improved kinematics thatcan reduce exhaust leakage;

FIG. 8 is a perspective view of an example of wastegate arm and plugcomponents provided as a subassembly;

FIG. 9 is a series of cross-sectional views of the example of FIG. 8,including a cross-sectional view of an example of an assembly with awastegate arm demonstrating improved kinematics that can reduce exhaustleakage;

FIG. 10 is a perspective view of an example of wastegate arm and plugcomponents provided as a subassembly;

FIG. 11 is a cross-sectional view of an example of an assembly with thewastegate arm and plug subassembly of FIG. 10 demonstrating improvedkinematics that can reduce exhaust leakage;

FIG. 12 is a series of views of the wastegate arm of FIG. 10 and anexample of a bushing configured for receipt of a portion of the arm;

FIG. 13 is a series of views of the wastegate plug of FIG. 10; and

FIG. 14 is a series of views of an example of an assembly that includesthe wastegate arm and plug of FIG. 10.

DETAILED DESCRIPTION

Turbochargers are frequently utilized to increase output of an internalcombustion engine. Referring to FIG. 1, a conventional system 100includes an internal combustion engine 110 and a turbocharger 120. Theinternal combustion engine 110 includes an engine block 118 housing oneor more combustion chambers that operatively drive a shaft 112 (e.g.,via pistons). As shown in FIG. 1, an intake port 114 provides a flowpath for air to the engine block 118 while an exhaust port 116 providesa flow path for exhaust from the engine block 118.

The turbocharger 120 acts to extract energy from the exhaust and toprovide energy to intake air, which may be combined with fuel to formcombustion gas. As shown in FIG. 1, the turbocharger 120 includes an airinlet 134, a shaft 122, a compressor 124, a turbine 126, a housing 128and an exhaust outlet 136. The housing 128 may be referred to as acenter housing as it is disposed between the compressor 124 and theturbine 126. The shaft 122 may be a shaft assembly that includes avariety of components. In the example of FIG. 1, a wastegate valve (orsimply wastegate) 135 is positioned proximate to the inlet of theturbine 126. The wastegate valve 135 can be controlled to allow exhaustfrom the exhaust port 116 to bypass the turbine 126.

In FIG. 1, an example of a controller 190 is shown as including one ormore processors 192, memory 194 and one or more interfaces 196. Such acontroller may include circuitry such as circuitry of an engine controlunit. As described herein, various methods or techniques may optionallybe implemented in conjunction with a controller, for example, throughcontrol logic. Control logic may depend on one or more engine operatingconditions. For example, sensors may transmit information to thecontroller 190 via the one or more interfaces 196. Control logic mayrely on such information and, in turn, the controller 190 may outputcontrol signals to control engine operation. The controller 190 may beconfigured to control a variable geometry assembly, a wastegate, anelectric motor, or one or more other components associated with anengine, an exhaust turbine (or exhaust turbines), a turbocharger (orturbochargers), etc. With respect to a wastegate, the controller 190 maybe configured to act as an actuator or to transmit a signal to anactuator configured to actuate, for example, the wastegate valve 135(e.g., to close or open a wastegate).

As described herein, various wastegates and wastegate components canoptionally reduce loading to ensure acceptable leakage at a plug/seatinterface of a wastegate opening or openings. In general, high loadrequirements generate high mechanical stresses in the kinematics partsof a wastegate, a fact which has led to significantly oversized partdesign to ensure requested reliability levels. In various examplesdescribed herein, an arm with a beveled surface can lead to asignificant reduction in system loading (e.g., up to 20% or morecompared to a conventional arm) while avoiding undesirable wastegateplug pre-opening. Such a beveled surface may be achieved by machining aconventional arm or by otherwise forming an arm with a beveled orclipped surface (e.g., from a plug axis up to a free end of the arm).Such an approach allows for relocation of an arm/plug loading pointtoward a plug center (e.g., optionally exactly at a plug center), whichcan, in turn, improve sealing efficiency with regard to both mechanicaland aerodynamic phenomena.

As described herein, in various examples, a wastegate arm and plug maybe configured as a ball and socket joint. For example, an arm mayinclude a ball portion while a plug includes a socket portion or a plugmay include a ball portion while an arm may include a socket portion.Such configurations can also allow for reduction in system loading whileavoiding undesirable wastegate plug pre-opening. As to a ball and socketjoint, one wastegate component may include only a portion of a “ball”,for example, a convex, at least partially spherical surface, and anassociated component may include a socket defined by a surface (e.g.,concave) for contacting the “ball”, which may be at least partiallyspherical or beveled or of another suitable, substantially complimentaryshape.

As described herein, use of a wastegate with a beveled surface or a balland socket joint can reduce exhaust leakage and improve low end behaviorof a turbocharged engine. In trials for a wastegate arm with a beveledsurface, both leak flow and on-engine low end performance have beenmeasured showing benefits over a conventional wastegate arm (e.g.,without a beveled surface). Further, as load is applied right at (e.g.,or more closely to) the center of a plug, such an approach also allows areduction of about 20% of the average load needed to ensure sealing of awastegate opening.

As described herein, various wastegates and wastegate components may beapplied to a conventional fixed nozzle turbine, a fixed-vaned nozzleturbine, a variable nozzle turbine, etc. As described herein, variouswastegates and wastegate components may be applied to a twin scrollturbocharger.

FIGS. 2 and 3 show example assemblies 200 and 300, each including awastegate. The assembly 200 and the assembly 300 each include a housing210 and 310, an exhaust flow chamber 220 and 320, a wastegate chamber230 and 330 and a wastegate valve control mechanism 240 and 340. For theassembly 200 of FIG. 2, the exhaust flow chamber 220 is separated fromthe wastegate chamber 230; whereas, for the assembly 300 of FIG. 3, thechamber 320 joins the wastegate chamber 330. Further, the assembly 300is shown as including a turbine wheel 322, which would be included inthe assembly 200, downstream from the chamber 220.

The wastegate control mechanism 240 of the assembly 200 includes acontrol arm 242, a shaft 243, and a poppet arm 250 for moving a plug 246between a fully closed position and a fully open position. As shown inFIG. 2, the plug 246 is connected and attached to the poppet arm 250 viaa peg or stem 244 and washer or retainer 245.

The wastegate control mechanism 340 of the assembly 300 includes acontrol arm 342, a shaft 343, and a poppet arm 350 for moving a plug 346between a fully closed position and a fully open position. As shown inFIG. 3, the plug 346 is connected and attached to the poppet arm 350 viaa peg or stem 344 and retainer 345. As shown in FIGS. 2 and 3, the plug246 of the assembly 200 has a different shape than the plug 346 of theassembly 300.

FIG. 4 shows a perspective view and a cross-sectional view of anassembly 400 that includes a wastegate. The assembly 400 includes ahousing 410, an exhaust flow chamber 420, a wastegate chamber 430 and awastegate valve control mechanism 440. Also shown in FIG. 4 are a volutewall 404 and a substantially cylindrical housing wall 408, which, atleast in part, defines the exhaust flow chamber 420.

The wastegate control mechanism 440 of the assembly 400 includes apoppet arm 450 for moving a plug 446 between a fully closed position anda fully open position. As shown in FIG. 4, the plug 446 is connected andattached to the poppet arm 450 via a peg or stem 444 and retainer 445.

The views of FIG. 4 also show the housing 410 as including an exhaustinlet 412, a volute chamber 414 and a passage 416 to a wastegate opening424 leading to the wastegate chamber 430 as well as an opening 418 todirect exhaust to a turbine wheel (see, e.g., the wheel 322 of FIG. 3).

Regulation of exhaust from the volute chamber 414 to the wastegatechamber 430 occurs via the wastegate control mechanism 440 where theplug 446 is configured to plug the opening 424. The plug 446 is operablyconnected to the poppet arm 450 such that movement of the poppet arm 450(e.g., via an actuator) can partially or fully open the opening 424(i.e., for “waste gating” exhaust). Accordingly, the wastegate controlmechanism 440 can control how much exhaust entering the assembly 400 viathe inlet 412 is directed to the turbine wheel space via the opening418. Exhaust flowing through the opening 424 to the wastegate chamber430 joins the flow of exhaust from the chamber 420. One or more exhaustsystem components (e.g., of a vehicle) may be connected to an opening oropenings of the assembly 400.

FIG. 5 shows a top view of a shaft and arm component 550, a side view ofthe arm 555 and a cross-sectional view through a portion of an assembly500 with a wastegate. As shown in the top view, the shaft and armcomponent 550 may be a unitary component that includes a shaft portion570 and an arm portion 555 located between a control end 551 and achamber end 553. The shaft 570 includes a central shaft portion 572disposed between a pair of journals 574 and 576 while the arm 555extends from the shaft 570 at an angle and includes an opening 556configured for receipt of a peg or stem 547 of a plug 546. As shown inthe side view, the arm 555 has a planar lower surface 558 and a planarupper surface 559 (e.g., lying in planes orthogonal to a z-axis,z_(arm), of the opening 556). As shown in the top view, the opening 556extends between the lower surface 558 and the upper surface 559 with aradius r (i.e., defined about z_(arm)).

The cross-sectional view of FIG. 5 shows the assembly 500 as including ahousing 510 that defines, at least in part, a volute chamber 514, awastegate passage 516, a wastegate opening 524 and a wastegate chamber530 where a wall of the wastegate chamber 530 includes a bore 511configured for receipt of the shaft 570.

As described herein, an actuator may actuate a mechanism attached at thecontrol end 551 of the shaft 570 to cause rotation of the shaft 570 inthe bore 511 for purposes of the plug 546 opening or closing thewastegate opening 524. As described, the plug 546 is attached to the arm555 via a peg or stem 547, which is received via the opening 556 in thearm 555. A portion 544 of the plug 546 may be part of the peg 547 or aseparate part of an attachment mechanism that may cooperate with aretainer 545 to retain the plug 546 with respect to the arm 555. Asdescribed herein, various issues can arise during operation, which leadto exhaust leakage from the volute chamber 514 to the wastegate chamber530 (e.g., via the passage 516 and the opening 524).

As shown in FIG. 5, the lower surface 558 of the arm 555 is planar and asurface 548 of the plug 546 is planar and orthogonal to a z-axis,z_(plug), of the plug 546. As the arm 555 rotates, the surface 558 andthe surface 548 may not align, as indicated by an angle φ betweenz_(arm) and z_(plug). In other words, for example, in a closedorientation of the plug 546 with respect to the opening 524, the planarsurface 558 of the arm 555 is not parallel to the planar surface 548 ofthe plug 546. While a design may call for these two surfaces to beparallel at a particular angle of rotation, in practice, properalignment, clearances, etc., may be difficult to achieve. Further, assubstantial force must be applied to the plug 546 by the arm 555,changes in clearances (e.g., asymmetries) or wear may occur of one ormore wastegate components such that any initial alignment is unlikely tobe maintained during life of the wastegate.

In the example of FIG. 5, a thick arrow indicates how the arm 555applies force to the plug 546 where the surfaces 548 and 548 are notparallel. Consequently, a gap exists between the arm 555 and the plug546, as indicated by smaller, dimensional arrows. The example of FIG. 5does not account for exhaust pressure, particularly high exhaustpressure in the volute chamber 514 and passage 516 and lower pressure inthe wastegate chamber 530. Thus, in the example of FIG. 5, a face 541 ofthe plug 546 is shown as being parallel to and in contact with a planarsurface 525 that surrounds the opening 524.

FIG. 6 shows a cross-sectional view of the assembly 500 where exhaustpressure exists in the passage 516, as indicated by a series of thickarrows that represent force of the exhaust against the face 541 of theplug 546. As the exhaust pressure forces the plug 546 upwards, the gapbetween the planar surface 548 of the plug 546 and the planar surface558 of the arm 555 closes as the plug 546 tilts. While the tilt of theplug 546 may cause z_(plug) and z_(arm) to align (decrease φ), it causesmisalignment of the face 541 and the surface 525 to thereby allow forleakage of exhaust from the opening 524 to the wastegate chamber 530.

As shown in FIGS. 2, 3, 4, 5 and 6, for a variety of reasons, wastegatevalves are configured to move a plug attached to an arm by rotating ashaft about its axis. Over time, clearances between the variouscomponents (e.g., plug, arm, shaft, shaft bore, bushings, etc.) canchange. Forces that can cause such change include aerodynamicexcitation, high temperatures, temperature cycling (e.g., temperatures<−20 degrees C. to >1000 degrees C.), chemical attack, friction,deterioration of materials, etc. For at least the foregoing reasons, itcan be difficult to maintain effective sealing of a wastegate openingover the lifetime of an exhaust turbine assembly. As to temperature,problems at high temperatures generally include wear and loss offunction and consequently leakage, lack of controllability or acombination of leakage and uncontrollability.

FIG. 7 shows a top view of an example of a shaft and arm component 750,a side view of an example of an arm 755 and a cross-sectional view of anexample of an assembly 700 that includes the arm 755 for improvedkinematics and reduction of exhaust leakage for a closed orientation ofa wastegate.

As shown in the top view, the shaft and arm component 750 may be aunitary component that includes a shaft portion 770 and an arm portion755 located between a control end 751 and a chamber end 753. In theexample of FIG. 7, the shaft 770 includes a central shaft portion 772disposed between a pair of journals 774 and 776 while the arm 755extends from the shaft 770 at an angle and includes an opening 756configured for receipt of a peg or stem 547 of a plug 546. As shown inthe side view, the arm 755 has lower and upper surfaces 758 and 759where a portion of the lower surface 758 is a beveled lower surface anda portion of the upper surface 759 is a beveled upper surface. Asdescribed herein, a beveled upper surface may be optional.

The cross-sectional view of FIG. 7 shows the assembly 700 as including ahousing 510 that defines, at least in part, a volute chamber 514, awastegate passage 516, a wastegate opening 524 and a wastegate chamber530 where a wall of the wastegate chamber 530 includes a bore 511configured for receipt of the shaft 770.

As described herein, an actuator may actuate a mechanism attached at thecontrol end 751 of the shaft 770 to cause rotation of the shaft 770 inthe bore 511 for purposes of the plug 546 opening or closing thewastegate opening 524. As described, the plug 546 is attached to the arm755 via a peg or stem 547, which is received via the opening 756 in thearm 755. A portion 544 of the plug 546 may be part of the peg 547 or aseparate part of an attachment mechanism that may cooperate with aretainer 545 to retain the plug 546 with respect to the arm 755. Asdescribed herein, the arm 755 can reduce exhaust leakage from the volutechamber 514 to the wastegate chamber 530 (e.g., via the passage 516 andthe opening 524).

As shown in FIG. 7, the lower surface 758 of the arm 755 includes abeveled portion and a surface 548 of the plug 546 is planar (e.g.,noting that the plug 546 may be symmetric and positioned or otherwiserotated at any angle with respect to the arm 755). In the example ofFIG. 7, as the arm 755 rotates, the bevel of the lower surface 758allows the arm 755 to contact the surface 548 at or near center of theplug 546 (e.g., to distribute force evenly across the face 541 of theplug 546). In other words, for example, in a closed orientation of theplug 546 with respect to the opening 524, the beveled portion of thelower surface 758 of the arm 755 has an angle sufficient to allow forcontact between the arm 755 and the plug 546 more centrally (i.e., nearthe peg 547 as received by the opening 756). Further, even where anangle may exist between a central axis of a plug and a central axis ofan opening of an arm, a beveled lower surface can provide for contactbetween the arm and the plug more centrally for application of forcefrom the arm to the plug, which, in turn, allows for more even sealingof the plug. Whether any contact occurs on the beveled portion of thelower surface may depend on a variety of factors (e.g., alignment, wear,etc.). Noting that contact between the plug 546 and part of the beveledportion of the lower surface 758 (e.g., near commencement of the bevel)can provide for transmission of force from the arm 755 more centrally tothe plug 546.

In the example of FIG. 7, thick arrows represent force applied by thearm 755 centrally to the plug 546 and distribution of the force to thesurface 525, which imposes, in sum, an equal and opposite force whereexhaust pressure is not present. Where exhaust pressure is present inthe passage 516, the force applied by the arm 755 to the plug 546 shouldbe sufficient to overcome the exhaust pressure experienced by the areaof the face 541. Hence, the beveled portion of the lower surface 758allows the arm 755 to avoid contact with the planar surface 548 of theplug 546 in a manner that might cause misalignment of contact and anopportunity for exhaust pressure in the passage 516 to tilt the plug 546and cause leakage from the passage 516 to the wastegate chamber 530 fora closed orientation.

For some applications, an arm may be symmetric such that uponinstallation in an assembly, a beveled surface may be an upper surfaceor a lower surface. Accordingly, such an arm may have two beveledsurfaces (see, e.g., the surfaces 758 and 759 of the side view of FIG.7). Further, in such an example, force may be applied more evenly to aretainer for raising a plug to allow for passage of exhaust to awastegate chamber and, correspondingly, decrease wear and increaselongevity of a wastegate assembly.

As described herein, a wastegate assembly can include a plug configuredto plug a wastegate opening where the plug includes a peg extending froma planar surface; a shaft configured for receipt by a bore in awastegate chamber; and a rotatable arm extending from the shaft wherethe arm includes a peg opening configured for receipt of the peg of theplug and where the arm includes a lower surface that includes a beveledportion, the lower surface configured to contact the planar surface ofthe plug for a closed orientation of the plug with respect to thewastegate opening. In such an example, the beveled portion of the lowersurface may have a bevel angle extending from a central axis of the pegopening toward a free end of the arm. As mentioned, an arm may include abeveled upper surface as well as a beveled lower surface.

As described herein, a plug may include a disk-shaped portion (e.g.,defined by a height and a diameter). A plug typically includes a faceconfigured to contact a surface surrounding a wastegate opening oropenings.

As described herein, a beveled lower surface of an arm may have a bevelangle greater than approximately 10 degrees. In general, a beveled lowersurface of an arm may have a bevel angle that depends on orientation ofthe arm with respect to a shaft and a closed orientation of a wastegateplug. For example, if a surface surrounding a wastegate opening definesa zero angle plane, the angle of an arm with respect to an axis ofrotation of a shaft may define the bevel angle required to avoidmisalignment between the arm and a plug configured to cover thewastegate opening. In general, the steeper the angle between the axis ofrotation and the plane of the wastegate opening, the steeper the bevel.In various examples, an arm may be configured to reduce the effect of asteep angle between an axis of rotation and a plane of a wastegateopening, which may be taken into account when determining a bevel angleand manufacturing an arm.

As mentioned, a wastegate can include a ball and socket joint. Examplesof wastegates with a ball and socket joint are shown in FIGS. 8 to 14.

FIG. 8 shows a perspective view of an example of a shaft and armcomponent 850 attached to a plug 840 along with a cylindrical coordinatesystem (r, z, Θ). In the example of FIG. 8, the shaft and arm component850 may be a unitary component that includes a shaft portion 870 and anarm portion 855 located between a control end 851 and a chamber end 853.The shaft portion 870 may include a central portion 872 and optionallyadditional features, for example, for attachment of a control componentfor rotating the shaft 870.

In the example of FIG. 8, the arm 855 includes a lower surface 858 andan upper surface 859 where an opening extends between the lower surface858 and the upper surface 859. As shown in FIG. 9, the plug 840 isattached to the arm 855 via a peg or stem 847, which is received via theopening 856 in the arm 855. A portion 844 of the plug 840 may be part ofthe peg 847 or a separate part of an attachment mechanism that maycooperate with a retainer 845 to retain the plug 840 with respect to thearm 855. The stem or peg 847 may have an axial height along a plug axis,z_(plug), and a radius that is slightly smaller than a radius of theopening 856 of the arm 855. During operation, fit between the arm 855and the plug 840 may adjust or adapt in a manner that helps to ensurethat force is transmitted from the arm 855 to the plug 840 morecentrally, such adjustment or adaptation may cause the arm axis z_(arm)and the plug axis z_(plug) to align or not align (e.g., depending onrotational angle of the arm 855 about an axis of the shaft 870 or otherfactors).

In the example of FIG. 8, the plug 840 includes an upwardly extendingridge 846 that spans an angle less than 360 degrees to accommodate thearm 855. As shown, the ridge 846 has a height that can be defined withrespect to the z-axis, a width that can be defined with respect to ther-axis and a span that can be defined with respect to the azimuthalangle Θ.

FIG. 9 shows a cross-sectional view of the shaft and arm component 850of FIG. 8, a cross-sectional view of the plug 840 of FIG. 8 and across-sectional view of an example of an assembly 900 that includes theshaft and arm component 850 and the plug 840 for improved kinematics andreduction of exhaust leakage for a closed orientation of a wastegate.

As shown in the cross-sectional view of the shaft and arm component 850of FIG. 9, the lower surface 858 and the upper surface 859 includeannular beveled or rounded portions adjacent the opening 856. Forexample, the lower surface 858 may be defined in part by an axial heightΔz_(ls) along a z-axis, z_(arm), where a radius of the lower surface858, along the r-axis, varies with respect to axial position (e.g.,decreasing approaching the opening 856). As described herein, theopening 856 may be defined by a radius along the r-axis and an axialheight along z_(arm) (e.g., Δz_(o)). In general, such an opening, asconfigured to receive a stem or peg of a plug, may define z_(arm). Inthe example of FIG. 9, both the lower surface 858 and the upper surface859 include portions with varying radii as they approach the radius ofthe opening 856. As described herein, the upper and lower surfaces 858and 859 may be symmetric about the azimuthal direction (e.g., an annularsurface with a constant radius for a given axial position) or vary aboutthe azimuthal direction (e.g., consider an annular surface with anelliptical or other shape). As described herein, the lower surface 858may be shaped to receive the plug 840 in a particular orientation;noting that the ridge 846, which may be optional, can act to orient theplug 840 with respect to the arm 855.

As shown in the cross-sectional view of the plug 840, a rounded portion848 has a radius along the r-axis that varies with respect to positionalong a z-axis, z_(plug). As described herein, the rounded portion 848may be symmetric about the azimuthal direction or vary about theazimuthal direction. In general, the shape of the rounded portion 848 ofthe plug 840 is substantially complimentary to the shape of the lowersurface 858 of the arm 855, particularly to allow for distribution offorce from the arm 855 to the plug 840 in a manner that acts to promotesealing and to avoid leaking of exhaust gas from a wastegate opening.Accordingly, while a rounded shape is shown for the portion 848 of theplug 840, an annular bevel or other shape may be provided thatcompliments the shape of a lower surface of an arm.

As shown in the cross-section view of the assembly 900, the beveled orrounded portion of the lower surface 858 is configured to contact therounded surface 848 of the plug 840. As described herein, such anarrangement may be referred to as a ball and socket joint. Specifically,in the example of FIGS. 8 and 9, the arm 855 has a socket configured forreceipt of a ball portion of the plug 840. The opening 856, which isconfigured for receipt of the stem 847, may be considered as beinglocated above the socket. In the example of FIGS. 8 and 9, someclearance exists between the opening 856 and the stem 847 (e.g., radialclearance) to allow for a small amount of axial misalignment, ifrequired, to promote seating of the rounded surface 848 against thelower surface 858 (e.g., consider a slight angle φ between z_(arm) andz_(plug)). In turn, effective, centralized transmission of force fromthe arm 855 to the plug 840 (e.g., as indicated by arrows representingforces) can promote seating of the face 841 against the surface 525 toenhance sealing of the wastegate opening 524. Also shown in the exampleof FIG. 9, the plug 840 includes a centrally located concave recess 843on the face 841, which may help to more favorably distribute forcesexerted by exhaust (e.g., during pulsations, etc.). Specifically, therecess acts to increase surface area about z_(plug), which can helpconcentrate force about z_(plug); noting that the configuration of thearm 855 and plug 840 also act to transmit force to about z_(plug). Asdescribed herein, a plug may optionally include a face surface featurethat helps to direct force exerted by exhaust to help an arm maintainthe plug in a closed orientation with respect to a wastegate opening.

As described herein, a wastegate assembly can include a plug configuredto plug a wastegate opening where the plug includes a stem or a pegextending from a rounded surface; a shaft configured for receipt by abore in a wastegate chamber; and a rotatable arm extending from theshaft where the arm includes an annular, beveled lower surface leadingto a peg opening configured for receipt of the peg of the plug, wherethe annular, beveled lower surface is configured to contact the roundedsurface of the plug for a closed orientation of the plug with respect tothe wastegate opening. In such an example, the plug can include anupwardly extending ridge configured to orient the plug with respect tothe arm.

As described herein, an arm can include an annular, beveled lowersurface and an annular, beveled upper surface where such surfaces join apeg (or stem) opening, which may define a central axis. A peg openingmay have a radius defined about a central axis, for example, where anannular, beveled upper surface and an annular, beveled lower surfacehave increasing radii with increasing axial distance from the pegopening.

FIG. 10 shows a perspective view of an example of a shaft and armcomponent 1050 attached to a plug 1040. In the example of FIG. 10, theshaft and arm component 1050 may be a unitary component that includes ashaft portion 1070 and an arm portion 1055 located between a control end1051 and a chamber end 1053. In the example of FIG. 10, the shaft 1070includes a central shaft portion 1072 disposed between a pair ofjournals 1074 and 1076 while the arm 1055 extends from the shaft 1070 atan angle and includes a bulbous portion with a convex, at leastpartially spherical surface 1052 from which various pegs extend 1054-1,1054-2, and 1054-3.

The plug 1040 includes a face 1041; two sockets formed by respectivepairs of bent posts 1042-1 and 1042-3 and 1042-2 and 1042-4; and aseries of guides 1044-1, 1044-2, 1044-3 and 1044-4. As shown, the pegs1054-2 and 1054-3 are received by the peg sockets while the guides1044-1 and 1044-2 guide the arm 1055 and the guides 1044-3 and 1044-4guide the peg 1054-1.

FIG. 11 shows a cross-sectional view of an example of an assembly 900that includes the arm 1055 and the plug 1040 of FIG. 10 with respect toa housing 510. In the example of FIG. 11, the convex, at least partiallyspherical surface 1052 of the arm 1055 is seated in a concave, at leastpartially spherical surface 1046 of the plug 1040. Such an arrangementof surfaces allows the arm 1055 to apply force centrally to the plug1040. Accordingly, misalignment that could result in tilting of the plug1040 with respect to a planar surface 525 surrounding a wastegateopening 524 is reduced or avoided. As described herein, such aconfiguration may be referred to as a ball and socket joint, where theplug 1040 provides a socket for a ball portion of the arm 1055.

FIG. 12 shows a series of views of the shaft and arm component 1050 aswell as a bushing 1090. As described herein, the shaft 1070 and the arm1055 may be a unitary component, for example, machined from a singlepiece of material. Alternatively, the shaft 1070 and the arm 1055 may beseparate component that are attached (e.g., by welding, a joint, etc.).For example, the arm 1055 may include a threaded socket for receipt of athreaded end of the shaft 1070. In another example, the arm 1055 may bewelded to the shaft 1070. As shown in a side view of FIG. 12, a bushing1090 may be provided with dimensions appropriate for seating in a boreof a housing. Such a bushing may be configured and arranged to reduceleakage of exhaust from a wastegate chamber to an exterior space. In theexample of FIG. 12, a control arm 1092 is also shown as being connectedto the shaft 1070 near its control end 1051.

FIG. 13 shows a series of views of the plug 1040. In a top view, thecentrally located surface 1046 is shown. In general, the surface 1046 isconcave and shaped to seat a ball-shaped portion of an arm (e.g., alonga convex surface) where the plug 1040 may move with some limited amountof rotation with respect to the arm. For example, as shown in FIG. 12,the pairs of posts 1042-1 and 1042-3 and 1042-2 and 1042-4 are bent toform peg sockets for receipt of pegs 1054-2 and 1054-3. In the exampleof FIG. 13, the posts 1042-1, 1042-2, 1042-3 and 1042-4 are shown instraight or unbent configurations.

As described herein, a method may position a plug with posts in awastegate chamber (e.g., optionally with guides), rotate an arm thatincludes pegs to position the arm with respect to the plug (e.g.,optionally with assistance from guides) and bend the posts to form pegsockets for two of the pegs. In another example, a method may includeassembling an arm and a plug prior to installing the arm and the plug ina wastegate chamber.

As described herein, a wastegate assembly can include a plug configuredto plug a wastegate opening where the plug includes a concave, at leastpartially spherical surface; a shaft configured for receipt by a bore ina wastegate chamber; and a rotatable arm extending from the shaft wherethe arm includes a convex, at least partially spherical surfaceconfigured for contacting the concave, at least partially sphericalsurface of the plug for a closed orientation of the plug with respect tothe wastegate opening.

As described herein, an arm can include at least a pair of pegs and aplug can include at least a pair of peg sockets configured for rotatablereceipt of the pegs. As mentioned, such peg sockets may be formed bybending posts.

As described herein, an arm may include a pair of pegs that extendoutwardly in a plane defined by a spherical surface of the arm.

As described herein, a plug can include a disk-shaped portion, a faceconfigured to contact a surface surrounding a wastegate opening, etc. Invarious examples, a plug can include a face configured to contact asurface surrounding more than one wastegate opening.

FIG. 14 shows various views of an example of an assembly 1400 thatincludes the arm 1055 and the plug 1040. The assembly 1400 includes ahousing 1410 that has two passages 1416-1 and 1416-2 that lead to twoopenings 1424-1 and 1424-2. A top view also shows a surface 1425 thatsurrounds both of the openings 1424-1 and 1424-2. In the example of FIG.14, the plug 1040 is shaped and sized to cover both of the openings1424-1 and 1424-2 at the same time.

As described herein, a turbine housing can include a wastegate chamberthat includes a wastegate opening, and a wastegate disposed in thewastegate chamber where the wastegate includes a plug configured to plugthe wastegate opening where the plug includes a surface; a shaftconfigured for receipt by a bore in a wall of the wastegate chamber; anda rotatable arm extending from the shaft where the arm includes asurface configured for contacting the surface of the plug for a closedorientation of the plug with respect to the wastegate opening. In suchan example, the surface may include a beveled surface or it may includea convex, at least partially spherical surface or it may be a concave,at least partially spherical surface (e.g., an annular beveled orrounded surface). The surface of a plug may be, for example, a planar,annular surface; a concave, at least partially spherical surface or aconvex, at least partially spherical surface.

As described herein, various acts may be performed by a controller (see,e.g., the controller 190 of FIG. 1), which may be a programmable controlconfigured to operate according to instructions. As described herein,one or more computer-readable media may include processor-executableinstructions to instruct a computer (e.g., controller or other computingdevice) to perform one or more acts described herein (e.g., opening orclosing a plug). A computer-readable medium may be a storage medium(e.g., a device such as a memory chip, memory card, storage disk, etc.).A controller may be able to access such a storage medium (e.g., via awired or wireless interface) and load information (e.g., instructionsand/or other information) into memory (see, e.g., the memory 194 of FIG.1). As described herein, a controller may be an engine control unit(ECU) or other control unit configured to control operation of awastegate valve (e.g., for purposes of engine performance, etc.).

Although some examples of methods, devices, systems, arrangements, etc.,have been illustrated in the accompanying Drawings and described in theforegoing Detailed Description, it will be understood that the exampleembodiments disclosed are not limiting, but are capable of numerousrearrangements, modifications and substitutions without departing fromthe spirit set forth and defined by the following claims.

What is claimed is:
 1. A wastegate assembly comprising: a plugconfigured to plug a wastegate opening wherein the plug comprises aconcave, at least partially spherical surface and a pair of peg sockets;a shaft configured for receipt by a bore in a wastegate chamber; and arotatable arm extending from the shaft wherein the arm comprises abulbous portion, a pair of pegs that extend outwardly from the bulbousportion, wherein the pair of peg sockets are configured for rotatablereceipt of the pair of pegs and wherein the bulbous portion comprises aconvex, at least partially spherical surface configured for contactingthe concave, at least partially spherical surface of the plug for aclosed orientation of the plug with respect to the wastegate opening. 2.The wastegate assembly of claim 1 wherein the plug comprises adiskshaped portion.
 3. The wastegate assembly of claim 1 wherein theplug comprises a face configured to contact a surface surrounding awastegate opening.
 4. The wastegate assembly of claim 1 wherein the plugcomprises a face configured to contact a surface surrounding more thanone wastegate opening.
 5. The wastegate assembly of claim 1 wherein thebulbous portion comprises a ball-shape.
 6. The wastegate assembly ofclaim 1 wherein the arm comprises three pegs.
 7. The wastegate assemblyof claim 6 wherein the three pegs extend outwardly from the bulbousportion in a plane.
 8. The wastegate assembly of claim 7 wherein the armextends from the shaft in the plane.
 9. The wastegate assembly of claim8 wherein a rotational axis of the shaft lies in the plane.
 10. Thewastegate assembly of claim 1 wherein the arm extends from the shaft atan angle with respect to a rotational axis of the shaft.
 11. Thewastegate assembly of claim 1 wherein the plug comprises guides thatguide the arm with respect to the plug.
 12. The wastegate assembly ofclaim 1 wherein the arm comprises a guide peg that extends outwardlyfrom the bulbous portion and wherein the plug comprises guides thatguide the guide peg.
 13. A turbocharger comprising: a compressorhousing; a center housing; and a turbine housing that comprises awastegate chamber, a bore, a wastegate opening and a wastegate assemblywherein the wastegate assembly comprises a plug configured to plug thewastegate opening wherein the plug comprises a concave, at leastpartially spherical surface and a pair of peg sockets; a shaftconfigured for receipt by the bore in the wastegate chamber; and arotatable arm extending from the shaft wherein the arm comprises abulbous portion, a pair of pegs that extend outwardly from the bulbousportion, wherein the pair of peg sockets are configured for rotatablereceipt of the pair of pegs and wherein the bulbous portion comprises aconvex, at least partially spherical surface configured for contactingthe concave, at least partially spherical surface of the plug for aclosed orientation of the plug with respect to the wastegate opening.14. A wastegate assembly comprising: a plug configured to plug awastegate opening wherein the plug comprises a concave, at leastpartially spherical surface and guides; a shaft configured for receiptby a bore in a wastegate chamber; and a rotatable arm extending from theshaft wherein the arm comprises a bulbous portion, a guide peg thatextends outwardly away from the bulbous portion, wherein the guidesguide the guide peg and wherein the bulbous portion comprises a convex,at least partially spherical surface configured for contacting theconcave, at least partially spherical surface of the plug for a closedorientation of the plug with respect to the wastegate opening.
 15. Thewastegate assembly of claim 14 wherein the plug comprises a diskshapedportion.
 16. The wastegate assembly of claim 14 wherein the plugcomprises a face configured to contact a surface surrounding a wastegateopening.
 17. The wastegate assembly of claim 14 wherein the plugcomprises a face configured to contact a surface surrounding more thanone wastegate opening.
 18. A wastegate assembly comprising: a plugconfigured to plug a wastegate opening wherein the plug comprises aconcave, at least partially spherical surface; a shaft configured forreceipt by a bore in a wastegate chamber; and a rotatable arm extendingfrom the shaft wherein the arm comprises a convex, at least partiallyspherical surface configured for contacting the concave, at leastpartially spherical surface of the plug for a closed orientation of theplug with respect to the wastegate opening wherein the arm comprisesthree pegs and wherein the plug comprises at least a pair of peg socketsand wherein the three pegs extend outwardly from the at least partiallyspherical surface in a plane.
 19. The wastegate assembly of claim 18wherein the arm extends from the shaft in the plane.
 20. The wastegateassembly of claim 19 wherein a rotational axis of the shaft lies in theplane.